This invention relates generally to electronic control systems and more specifically is directed to a controller for use in a multi-component video signal display and recording system.
The television receiver no longer stands alone as the sole member of a typical home video entertainment center. Today, in increasing numbers such video entertainment devices as video tape recorders (VTR's) and video record, or disc, players are becoming increasingly popular and available. Thus, the development of the home video entertainment center appears to be paralleling the development of the modular approach taken in the audio equipment field.
A centralized system is best implemented by means of a single controller for directing the operation of the individual components and for providing the necessary interfacing therebetween. The increasing complexity and versatility of the various available home video devices has placed demanding performance requirements upon a home video control system. For example, the rapid growth of cable television (CATV) has greatly expanded television programming available to the public. The increasing use of satellite communications and the expanding number of FCC-authorized subscription television (STV) stations promises to even further increase television programming available to the viewing public. This increase in the complexity and flexibility of currently available home video equipment and the growing number of television stations has resulted, in general, in home entertainment equipment controllers which are overly complex and difficult to operate. While a detailed (and complex) set of operating instructions generally accompany such equipment, the typical viewer has difficulty when attempting to fully grasp and master the operation of the device and hence is unable to take advantage of its full capability.
Because of the increased number of home video and television accessories, each of which has an RF-TV signal output, conventional video equipment control systems heretofore proposed have generally introduced undesirable distortion, noise or interference into the transmitted signals. For example, the front panel pushbutton selectors in these devices are generally used for mechanically switching the RF signals. These mechanical switches become noisy after extended use causing a degradation of the received video signal. In addition, the use of RF signal splitters in a conventional controller reduces the level of the television signals by as much as 8 dB. This signal loss is experienced not only during the simultaneous viewing and recording of a single signal, but also when one signal is being viewed while another is recorded.
Furthermore, conventional video equipment control systems using mechanical switching of the RF-TV signals are severely limited as to the degree of isolation between the various signal inputs and also the degree of EMI shielding which can be achieved while remaining cost effective.
U.S. Pat. No. 3,484,548 to Kowal et al. describes one approach for controlling the distribution of broadcast and recorded video information among various video signal processing devices. Described therein is a control center adapted to be connected to a video tape recorder, a conventional television receiver, and a television camera which is primarily comprised of a multi-section, rotary switch. As such, this mechanical switch directly couples the various components in the system and tends to become noisy with extended use in exhibiting the previously discussed operating limitations.
U.S. Pat. No. 4,031,548 to Kato discloses a combination of a television receiver and a VTR for recording and/or reproducing television signals wherein the television receiver has at least two signal selecting and receiving circuitries, each including a separately tuneable tuner, an intermediate frequency stage and a detecting stage. This system further includes two signal distributors, or splitters, for dividing the received television signals into two separate signals in providing the thus divided signal to the two signal selecting and receiving circuits. The signal losses inherent in such a system have been previously discussed and result from the attempt to accommodate the VTR using conventional television receiver circuitry. In addition, this system is designed for incorporation in the television receiver itself and thus relies upon the aforementioned complex and expensive conventional television receiver circuitry for its implementation therein.
In a control system where the signal inputs must be switched to two outputs rather than a single output, signal splitting is required to provide the proper signal path therebetween. Where there are a number of series switching stages in each potential signal path, groups of switches are required to perform each and every mode of operation. Conventionally in such systems, an extensive control matrix is provided for directing a particular input signal to the desired output. Of course, the more complex the switching matrix, the more tedious it is to utilize the system. The present invention, however, avoids the aforementioned problems by utilizing electronic RF switching, along with the interface capabilities of the video recording device and television receiver, controlled by a unique and novel arrangement of D.C. control switches.